Process for obtaining hydrocarbons from producing sands



mm. m, W32. WA D 4 mmww PROCESS FOR OBTAINING HYDROCARBONS FROMPRODUCING SANDS Filed Nov. 15, 1928 3 Sheets-Sheet l F. A. HOWARD Jan.19, 1932. 1,842,098

PROCESS FOR OBTAINING HYDHOCARBONS FROM PRODUCING SANDS Filed Nov. 15,1928 3 Sheets$heet 2 W I Q W Q 33x 1 1w 8 mm F. A. HOWARD Jim. w, H932.

PROCESS FOR OBTAINING HYDROCARBONS FROM PRODUCING SANDS Filed Nov. 15,1928 3 Sheets-Sheet 3 vNDO l mvu WWZNQQO @51 MA/ @btowwg,

Patented den. 1%, lEE

UNlTED FRANK A. HOWARD, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO STANDARDOIL DEVELOPMENT COMPANY, A CORPORATION OF DELAWARE PROCESS FOR OBTAININGHYDROOARBONS FROM PRODUCING- SANDS Application filed November 15, 1928.Serial No. 319,523.

The present invention relates to the art of obtaining valuablehydrocarbons from the earth and more specifically comprises an 1mprovedsystem for the recovery of volatile hydrocarbons from producingsandsbyapplication of high vacuum. My invent on w1ll be fully understood fromthe following description and the drawings which lllnstrate a suitablemeans for accompllsh'mg my improved method.

In the drawings, Fig. 1 is a sectional view broken so as to show theearths surface and the producing sands and the neighborlng strata withmine tunnels, ventilation tunnels, and the pipe system for thecollection of hydrocarbons;

Fig. 2 is a plan view taken in sectlon along line H-H of Fig. 1; and

Fig. 3 is a semi-diagrammatic view in sec tion of a portion of thepiping which may be substituted for that illustrated in Flg. 1 and Fig.2; and

Fig. 4 is a section elevation of an out-cropping producing stratum towhich my method is applied, showing the ground surface and a tunneldriven directly into the stratum.

In. a copending application, Serial No. 296,006, filed July 2a, 1928 inthe name of Warren K. Lewis, a method for obtaining volatilehydrocarbons from producing sands by application of high vacuum isdisclosed. My present method is an improvement of the above notedprocess and has for one of its objects a more complete utilization ofthe high vacuum by greatly increasing the area of thesand upon which thevacuum is effective and decreasing the frictional losses caused bypassage of gas through thick strata of sand and long pipes while underlow pressure. Other objects and advantages of the present method will beapparent to those skilled in the art.

Referring to the drawings, Fig. 1 and Fig. 2, reference character 1denotes a shaft extending from the ground surface to a point above orbelow the producing sands, shown generally at A. Cap rocks B and B areshown above and below the sands. The shaft is lined with concrete 2 andis divided into two parts by a partition 3, the working shaft denoted bynumeral 4 and the air shaft by 5.

The lower end of shaft 1 is shown below cap rock B but it should beunderstood that if desired the shaft may be terminated just above caprock B. From the lower end of the shaft, two sets of tunnels, 6 and 7,are mined parallel to the producing sand but separated therefrom by thecap rook. Tunnels 6 are mine tunnels and connected into the workingshaft 41, while tunnels 7, which run parallel to tunnels 6, are providedfor ventilation. A single tunnel may be made if desired and separatedinto the two parts by a partition. Tunnels 7 are connected with theventilation shaft 5 and a fan 6 is provided to force fresh air intoshaft 5. At intervals of about 100 feet, air passages 8 are bored toconnect tunnels 6 and 7 so that air passes out of the mine by shaft 4,as will be understood.

In the plan view, Fig. 2, the parallel arrangement of the tunnels isbest shown and they are constructed so as to form a net work of passagesbelow or above the producin sand which is thus divided into areas G, preerably square and each enclosing about acres. Where it is necessary fortunnels 6 and 7 to cross, tunnel 7 will be overor undercast, asindicated at D.

lfn each of the tunnels 6, a main collection manifold 9 is providedextending the length of the tunnel and at short intervals along itslength collection pipes 10 extend slantwise into the various areas ofsand bounded by the tunnels, as will be understood. Pipes 10 are sealedinto the cap rock as at 11 and the sand around each pipe is reamed outas at 12 into a cavity which exposes a large area of the sand.

The manifold pipes 9 are preferably laid on a slight inclination and atthe lowest point a separation tank 13 is provided, into which themanifolds drain. A vacuum pump 1 withdraws vapor from tank 13 and afterpassage through cooler 15, the mixture of gas and liquid condensate isdischarged into a second separator tank 16. Gas from tank 16 then passesup through line 17 to the earths surface and may there be treated forthe extraction'of gasoline by any suitable system. The system showncomprises a compressor 18, cooler 19, and condensate separation drum 20from which gas is withdrawn by line 21 and liquid to storage (not shown)by line 22.

Two liquid pumps, 23 and 24, are provided to force liquid from-drums l3and 16 respectively to earths surface by lines 25 and 26 to storage (notshown).

In Fig. 3 a modification of the collection method is shown. Collectionpipes 10, sealed into the rock at 11 are fitted with ejector nozzles 27,the collection pipe entering the nozzle at the side at about the pointof minimum cross sectional area, as will be understood. High pressuregas is fed to the nozzles by supply pipe 28 and the flow is controlledby a valve 29. Steam may be used as the high pressure medium, ifdesired, but preferably gas from the gasoline recovery system iscompressed to a suitable pressure and returned to the mine by pipe lines(not shown).

In Fig. 4, my method is applied to an outcropping stratum A, bounded asbefore by cap rocks B and B. Shaft 1 and tunnels 6 may be omitted inthis case and a large, long cavity 12 is driven directly into thestratum A. It will be understood that this method is to be applied to anoil sand relatively free of gas, either so by nature or by longapplication of vacuum according to present practice. If gas is presentin moderate or large quantities, a tunnel may be dug above or below thestratum A, as in Fig. 1. Cavity 12 may go back into the sand for aconsiderable distance and many such cavities may be provided at shortintervals, horizontally and vertically if the stratum be large, althoughonly one is shown in Fig. 4. The opening of cavity 12 is closed by amaterial ll -impervious to oil and gas, such as cement, and a pipe 10 issealed in for removal'ofvapor. Pipe 10 com-- municates with separatordrum 13, vacuum pump 14, cooler 15 and condensate drum 16, as shown inFigs. 1 and 2.

I have observed that it has been impossible.

, heretofore to maintain a high vacuum on any considerable body ofsands. This is due to the frictional loss caused by passage of vaporthrough a relatively thick stratum of sand,'

and because of the fact that the area of exposed sand is relativelysmall. The production of volatile vapors is also greatly restricted. Bymy method, however, it is possible to greatly increase the area throughwhich vapor is passed and to also greatly reduce the thickness of thelayer through which it passes. It is therefore capable of producingvapors from the sand at a rate which is much greater than is heretoforeobtained. Vacuua of 29 to 29.5 inches of mercury are maintained on largeareas with large yields of vapors. It is highly desirable to prevent allleakage of air or other gas into the producing stratum, particularly inthe neighborhood of the vapor i cs 10. Old oil wells and out-croppingshoul preferablybe sealed.

It is desirable to automatically control the ventilating fan 6 by theanalysis of the gas in the mine, whereby the concentration of methaneand the like may be kept below the dangerous limit. The tunnels'may alsobe constructed in anysuitable manner and need not be made strictlyaccording to the description, although that method is preferred.

My invention is not to be limited by any theory of the operation of myprocess nor by any illustrative example, but only by the followingclaims in which I wish to claim all novelty inherent in the invention.

I claim:

1. Process for obtaining hydrocarbon vapor from a stratum containing thesame, comprising forming mine galleries adjacent the stratum, removinglarge amounts of solid material from the stratum ata plurality ofpoints, whereby extended areas are laid open to the influence of reducedpressure, inserting pipes to tap said extended areas, flowing a streamof high pressure gas in a generally downward direction adjacent thepoint of outlet of such pipes and in communication therewith, whereby ahigh vacuum is produced in said extended areas, withdrawing thehydrocarbon vapor with the high pressure gas, and recovering condensableconstituents from the mixture.

2. Process for obtaining hydrocarbon vapor from a stratum containing thesame, comprising forming mine galleries adjacent the stratum, removinglarge amountsof solid material from the stratum at a plurality ofpoints, whereby a corresponding plurality of extended areas are laidopen, inserting pipes to tap said extended areas, flowing a stream ofhigh pressure gas adjacent the point of outlet of such pipes and incommunication therewith, whereby a high vacuum is produced in saidextended areas, withdrawing the hydrocarbon vapor with the high pressuregas, recovering condensable constituents from the mixture, compressingthe residual gas, and returning at least a portion of the same to thestratum as said stream of high pressure gas.

3. Process according to claim 2, in which the high pressure gas iscaused to produce a vacuum in the extended areas of about 29-29.5 inchesof mercury.

